In an electrical power network (such as a home or office network including outlets, hot wires, neutral wires, ground wires, etc.) a ground fault is a current leak that occurs when an energizing conductor (hot or neutral wire) faults to the outside or frame or chassis of an electrically powered device. If the hot wire in an electrical network faults to a grounded chassis, the current flow may be enough to seriously injure or kill someone touching the chassis. Furthermore, if a neutral conductor faults to ground, the chassis may still be a source of dangerous fault currents.
Ground-fault circuit interrupters (herein GFCIs) are designed to automatically shut off power to a load such as electrical equipment if a difference (i.e., an imbalance) between the hot conductor current and neutral conductor current is detected. Simply, the GFCI monitors the amount of current flowing from the Hot to the Neutral, and if there is any imbalance it trips the circuit. GFCI""s accomplish the above typically by testing for two conditions: (1) A Hot to Ground (safety/earth) fault. Current flows from the Hot wire to Ground bypassing the Neutral. This is the test that is most critical for safety. (2) A grounded Neutral fault. Due to mis-wiring or a short circuit, the neutral and ground wires are connected by a low resistance path downstream of the GFCI. In this case, the GFCI will trip as soon as power is applied even if nothing is connected to its protected (load) circuit.
Electrical power networks such as household wiring networks may include a number of GFCI outlets, which contain the necessary circuitry to detect current imbalances and trip circuits if necessary. Other downstream receptacles (outlets) connected in series to a particular GFCI are protected by that GFCI.
A GFCI will usually contain a xe2x80x9ctestxe2x80x9d button and a xe2x80x9cresetxe2x80x9d button. The xe2x80x9ctestxe2x80x9d button causes a small difference between the xe2x80x9chotxe2x80x9d and xe2x80x9cneutralxe2x80x9d currents to test the GFCI. For example, if a lamp were plugged into an outlet protected by a GFCI and turned on, and the test button pressed on the GFCI, the GFCI would apply an xe2x80x9cextraxe2x80x9d current and if it is functioning properly will detect the imbalance and trip the circuit. The lamp would subsequently turn off. The xe2x80x9cresetxe2x80x9d button, while pressed, opens the neutral connection and resets the GFCI. Once the xe2x80x9cresetxe2x80x9d button is pressed and released, the GFCI is reset, and the neutral is closed.
Typically, prior art methods for testing whether an outlet is protected by a particular GFCI (i.e., continuity testing) require that power to the electrical network be turned on. In the prior art method a load, such as a lamp, is plugged into a receptacle suspected to be protected by a particular GFCI. The test button on the GFCI is pressed and if the receptacle is protected by that GFCI, the equipment plugged into that receptacle turns off. Also, a prior art receptacle tester may be used which may be plugged into any outlet suspected of being connected to a particular GFCI. A button on the receptacle tester trips the GFCI connected to that receptacle. The receptacle, if protected by a GFCI, would then be non-functional. A user then would have to press the xe2x80x9cresetxe2x80x9d button on the GFCI suspected to protect the particular receptacle and again determine if the receptacle is functional. If the receptacle was functional again, the GFCI which had its reset button pressed and released would be determined to be connected to that particular receptacle.
To measure the actual trip current of a GFCI requires a GFCI tester. The tester allows a person to read the actual GFCI trip current on a meter, identifying the GFCI""s that do or do not operate within the required milli-amp range (usually four to six milli-amps).
There are a number of problems with the prior art method of determining whether a particular receptacle is connected to a GFCI. If testing requires tripping the GFCI, the power to the electrical network must be turned on, generally increasing the risk of electrical shock. Furthermore, if testing for whether a receptacle is connected to a GFCI requires tripping the GFCI by pressing the xe2x80x9ctestxe2x80x9d button, it is inconvenient in that either two people must be involved (i.e., one to push the test button, and the other to determine if a particular outlet is functioning) or one person must first press the test button and then travel to the location of the receptacle to determine if it is functioning.
One aspect of the present invention is to provide a method of testing for whether or not a particular outlet is connected to a particular GFCI, which eliminates the need for having the electrical network turned on.
Another aspect of the present invention is to provide a method and apparatus for testing whether or not a particular outlet is connected to a particular GFCI, which eliminates the need for tripping the GFCI.
Yet another aspect of the present invention is to provide a method of testing for whether or not a particular outlet is connected to a particular GFCI, which allows one individual to conveniently test multiple receptacles without having to go back and forth from the GFCI and the receptacle.
These and other aspects are achieved by the apparatus and system of the present invention which, in accordance with a broad structural aspect of the invention, include a circuit device with a power source, an output device (such as a light for example) which derives power from the power source, and connection prongs. One embodiment of the present invention is adapted to mate with a standard three prong receptacle in an electrical network, where the power to the electrical network is turned off. At some point in an electrical network, the ground and the neutral should be connected together. When the device of the present invention mates with the electrical network, a circuit is completed, allowing the output device to derive power from the power source and activate. If the reset button is then pressed on a particular GFCI, the neutral wire should open. If the receptacle that the device is plugged into is connected to the GFCI whose reset button is pressed, the circuit should break, and the output device should turn off, thus indicating the receptacle is connected to that GFCI. If the output device does not turn off, this may indicate faulty wiring or that the receptacle may be connected to another GFCI.
In another exemplary embodiment, the present invention includes a first circuit apparatus with three standard prongs, and an output device (such as a light for example) connected to two of the prongs which are adapted to mate with the xe2x80x9chotxe2x80x9d and xe2x80x9cneutralxe2x80x9d connections on a receptacle in an electrical network. This exemplary embodiment also includes a second circuit apparatus with three standard prongs, a power source connected to two of the prongs which are adapted to mate with the xe2x80x9chotxe2x80x9d and xe2x80x9cneutralxe2x80x9d connections on a receptacle in an electrical network.
The second circuit apparatus is plugged into a receptacle, such as a GFCI receptacle. The first circuit apparatus is plugged into a different receptacle, suspected to be connected to the GFCI receptacle. If the receptacles are in fact connected, a circuit will be completed, allowing the output device of the first apparatus to derive power from the power source of the second apparatus and activate. This would indicate the receptacles are connected.